1. Field
Exemplary embodiments of the present invention relate to a semiconductor device.
2. Description of the Related Art
FIG. 1 is a diagram for explaining a repair operation of a semiconductor memory device.
Referring to FIG. 1, a semiconductor memory device may include a cell array 110, a row control unit 120, and a column control unit 130. The cell array 110 may include a plurality of memory cells, the row control unit 120 may enable a word line selected by a row address RADD, and the column control unit 130 may access (read or write) data of a bit line selected by a column address CADD.
A row fuse circuit 140 may store a row address, corresponding to a memory cell having a defect in the cell array 110, as a repair row address REPAIR_RADD. A row comparison unit 150 may compare the repair row address REPAIR_RADD stored in the row fuse circuit 140 to a row address RADD inputted from outside the memory device. When the repair row address REPAIR_RADD coincides with the row address RADD, the row comparison unit 150 may control the row control unit 120 to enable a redundancy word line instead of a word line designated by the row address RADD.
A column fuse circuit 160 may store a column address, corresponding to a memory cell having a defect in the cell array 110, as a repair column address REPAIR_CADD. A column comparison unit 170 may compare the repair column address REPAIR_CADD stored in the column fuse circuit 160 to a column address CADD inputted from outside the memory device. When the repair column address REPAIR_CADD coincides with the column address CADD, the column comparison unit 170 may control the column control unit 130 to access a redundancy bit line instead of a bit line designated by the column address CADD.
The fuse circuits 140 and 160 of FIG. 1 may include a laser fuse. The laser fuse may store logic high or low data depending on whether the fuse is cut or not. The laser fuse may be programmed at a wafer level, but cannot be programmed after a wafer is mounted in a package. Furthermore, the laser fuse is difficult to be designed in a small size, due to a pitch limit. In order to overcome such a disadvantage, an E-fuse may be used. The E-fuse may be formed using a transistor or a capacitor resistor. When the E-fuse is formed using a transistor, the E-fuse may store data by changing resistance between gate and drain/source.
FIG. 2 is a diagram illustrating an E-fuse formed of a transistor and operating as a resistor or a capacitor.
Referring to FIG. 2, the E-fuse may include a transistor T. When a normal power supply voltage which the transistor T can stand is applied to a gate G, the E-fuse operates as a capacitor C. Thus, no current flows between the gate G and a drain-source D/S. However, when a high voltage which the transistor T cannot stand is applied to the gate G, the gate G and the drain-source D/S are short-circuited while gate oxide of the transistor T is broken. Then, the E-fuse operates as a resistor R. Thus, current may flow between the gate G and the drain-source D/S.
Data of the E-fuse may be recognized through the resistance value between the gate G and the drain-source D/S of the E-fuse. The data of the E-fuse may be directly recognized without a separate amplifying operation when the E-fuse is large. When the E-fuse is small, on the other hand, an amplifier may be used to sense a current flowing through the transistor T thereof. The above-described two methods have area limits because the transistor T forming the E-fuse needs to be large or the amplifier for amplifying data needs to be provided for each E-fuse.
Due to the above-described area issues, it is not easy to apply the E-fuse to fuse circuits 140 and 160. Thus, research has been conducted on a method in which E-fuses are formed in an array, and a repair operation is performed using data stored in the E-fuse array. When the E-fuses are formed in an array, an amplifier may be shared to reduce the total area consumed.
In the case of a semiconductor device including a nonvolatile storage unit such as an E-fuse array, repair data stored in the E-fuse array may be transmitted to storage units included in the semiconductor device, for example, latches, during a boot-up operation, in order to use the repair data stored in the E-fuse array. When the duplicate repair data is stored in the nonvolatile storage unit, an error may occur in the operation of the semiconductor device when the duplicate data is transmitted to the storage units.